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#1 2006-04-29 09:31:06

david_power
Member
Registered: 2006-04-29
Posts: 1

A Question......

Hello everyone, hope ur all well. i was going through trying to find a good maths forum when i came across this......seems an awesome place. ok i have this question for my maths problem, hope any of u can help me:

Q:    Given that  I=3*sin*wt       and           Ij=4*sin*(wt - pi/4)

1) We need to find Ih = I + Ij

and

2) By calculation find the resultant current Ih in the form:

               Ih = A*sin(wt + a)

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#2 2006-04-29 23:40:48

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

Re: A Question......

I made a crude graph of the situation in Excel. I'm not sure how clear it will turn out though. But if it does, then dark blue is I, purple is Ij and light blue is Ih.

(I graphed it using degrees instead of radians, but it gives the same thing)

This shows that Ih is a sine wave that has been shifted slightly.

You could use that graph to estimate the amplitude and shift, or you could probably do it mathematically as well. Somehow.

View Image: 4david.JPG

Why did the vector cross the road?
It wanted to be normal.

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